We now omit corrections from air friction, and put for definiteness \(a=100~\mu \) m, \(P_0= 100~\) W. The moment of inertia about the \(z\)  axis is \(I= (2/5)Ma^2\) , where \(M =4~\mu \) g is the mass. From earlier experimental tests of the equivalence principle [1]}, [2]}, we adopt the relationship \(I\Omega ^2 \sim 10^{-9}~\) N m/rad, where \(\Omega \)  as before is the undamped angular frequency of the test body. This leads to
\(\Omega \sim 10^3 \, \rm {rad\, s}^{-1}. \) 
